Quantum Fisher information is used to witness the quantum phase transition in a non-Hermitian trapped ion system with balanced gain and loss,from the viewpoint of quantum parameter estimation.We formulate a general no...Quantum Fisher information is used to witness the quantum phase transition in a non-Hermitian trapped ion system with balanced gain and loss,from the viewpoint of quantum parameter estimation.We formulate a general non-unitary dynamic of any two-level non-Hermitian system in the form of state vector.The sudden change in the dynamics of quantum Fisher information occurs at an exceptional point characterizing quantum criticality.The dynamical behaviors of quantum Fisher information are classified into two different ways which depends on whether the system is located in symmetry unbroken or broken phase regimes.In the phase regime where parity and time reversal symmetry are unbroken,the oscillatory evolution of quantum Fisher information is presented,achieving better quantum measurement precision.In the broken phase regime,quantum Fisher information undergoes the monotonically decreasing behavior.The maximum value of quantum estimation precision is obtained at the exceptional point.It is found that the two distinct kinds of behaviors can be verified by quantum entropy and coherence.Utilizing quantum Fisher information to witness phase transition in the non-Hermitian system is emphasized.The results may have potential applications to non-Hermitian quantum information technology.展开更多
We propose a scheme for generating a four-particle cluster state in an ion-trap system.The scheme isinsensitive to the thermal motion of the ions,and needs less operations than previous ones.With such a setup,we alsod...We propose a scheme for generating a four-particle cluster state in an ion-trap system.The scheme isinsensitive to the thermal motion of the ions,and needs less operations than previous ones.With such a setup,we alsodemonstrate a procedure for perfectly teleporting an arbitrary two-particle state via a single multipartite entanglementchannel,a four-particle cluster state.展开更多
We propose two schemes for the implementation of quantum discrete Fourier transform in the ion trap systern. In each scheme we design a tunable two-qubit phase gate as the main ingredient. The experimental implementat...We propose two schemes for the implementation of quantum discrete Fourier transform in the ion trap systern. In each scheme we design a tunable two-qubit phase gate as the main ingredient. The experimental implementation of the schemes would be an important step toward complex quantum computation in the ion trap system.展开更多
We propose a simple scheme for deterministic and multi-controlled teleportation of an arbitrary unknown two-level two-ion state in ion-trap system. In the scheme, the special entangled W states used as quantum channel...We propose a simple scheme for deterministic and multi-controlled teleportation of an arbitrary unknown two-level two-ion state in ion-trap system. In the scheme, the special entangled W states used as quantum channels and the requisite unitary transformations may be achieved via a single resonant interaction, respectively. The required time to complete the whole procedure does not increase with the number of agents.展开更多
Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for ...Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for a universal circuit is given based on the qudit system,which is larger and can store more information.In order to prove its universality for quantum applications,an explicit set of one-qudit and two-qudit gates is provided for the universal qudit computation.The one-qudit gates are general rotation for each two-dimensional subspace while the two-qudit gates are their controlled extensions.In comparison to previous quantum qudit logical gates,each primitive qudit gate is only dependent on two free parameters and may be easily implemented.In experimental implementation,multilevel ions with the linear ion trap model are used to build the qudit systems and use the coupling of neighbored levels for qudit gates.The controlled qudit gates may be realized with the interactions of internal and external coordinates of the ion.展开更多
文摘Quantum Fisher information is used to witness the quantum phase transition in a non-Hermitian trapped ion system with balanced gain and loss,from the viewpoint of quantum parameter estimation.We formulate a general non-unitary dynamic of any two-level non-Hermitian system in the form of state vector.The sudden change in the dynamics of quantum Fisher information occurs at an exceptional point characterizing quantum criticality.The dynamical behaviors of quantum Fisher information are classified into two different ways which depends on whether the system is located in symmetry unbroken or broken phase regimes.In the phase regime where parity and time reversal symmetry are unbroken,the oscillatory evolution of quantum Fisher information is presented,achieving better quantum measurement precision.In the broken phase regime,quantum Fisher information undergoes the monotonically decreasing behavior.The maximum value of quantum estimation precision is obtained at the exceptional point.It is found that the two distinct kinds of behaviors can be verified by quantum entropy and coherence.Utilizing quantum Fisher information to witness phase transition in the non-Hermitian system is emphasized.The results may have potential applications to non-Hermitian quantum information technology.
基金Supported by the National Natural Science Foundation of China under Grant No.10674018the National Fundamental Research Program of China under Grant No.2004CB719903
文摘We propose a scheme for generating a four-particle cluster state in an ion-trap system.The scheme isinsensitive to the thermal motion of the ions,and needs less operations than previous ones.With such a setup,we alsodemonstrate a procedure for perfectly teleporting an arbitrary two-particle state via a single multipartite entanglementchannel,a four-particle cluster state.
基金The project supported by National Natural Science Foundation of China under Grant No. 10225421 and Funds from Fuzhou University
文摘We propose two schemes for the implementation of quantum discrete Fourier transform in the ion trap systern. In each scheme we design a tunable two-qubit phase gate as the main ingredient. The experimental implementation of the schemes would be an important step toward complex quantum computation in the ion trap system.
基金Supported by National Natural Science Foundation of China under Grant Nos.60878059 and 10947147the Funds of Educational Committee of Fujian Province under Grant Nos.JA09014 and JB08066the Funds from Fujian Normal University under Grant No.2008100220
文摘We propose a simple scheme for deterministic and multi-controlled teleportation of an arbitrary unknown two-level two-ion state in ion-trap system. In the scheme, the special entangled W states used as quantum channels and the requisite unitary transformations may be achieved via a single resonant interaction, respectively. The required time to complete the whole procedure does not increase with the number of agents.
基金supported by the National Natural Science Foundation of China(Grant Nos.61303039 and 11226336)the Fundamental Research Funds for the Central Universities(Grant No.2682014CX095)the Science Foundation Ireland(SFI)under the International Strategic CooperationAward Grant Number SFI/13/ISCA/2845
文摘Quantum circuit model has been widely explored for various quantum applications such as Shors algorithm and Grovers searching algorithm.Most of previous algorithms are based on the qubit systems.Herein a proposal for a universal circuit is given based on the qudit system,which is larger and can store more information.In order to prove its universality for quantum applications,an explicit set of one-qudit and two-qudit gates is provided for the universal qudit computation.The one-qudit gates are general rotation for each two-dimensional subspace while the two-qudit gates are their controlled extensions.In comparison to previous quantum qudit logical gates,each primitive qudit gate is only dependent on two free parameters and may be easily implemented.In experimental implementation,multilevel ions with the linear ion trap model are used to build the qudit systems and use the coupling of neighbored levels for qudit gates.The controlled qudit gates may be realized with the interactions of internal and external coordinates of the ion.
